The present invention relates to extendible ladders. In particular, the invention relates to an extendible ladder housed in a sealed housing for use in escaping from an elevated structure such as a building.
Designs of extendible ladders are well known in the art. Such ladders typically collapse in a lateral or horizontal plane or fold in a vertical direction. Rope ladders which may be rolled for storage are also known in the art.
Ladders which fold in the vertical direction are of particular use for emergency escape purposes. For example, such a ladder may be stored near a window in an elevated floor of a home, or an apartment building. During an emergency, the ladder may be retrieved by an occupant and hung from the window ledge. By extending the rungs of the folded ladder, the occupant can provide an escape through the window to ground.
This type of foldable, extendible escape ladder is described in U.S. Pat. No. 4,751,982 to Wolfe. In the Wolfe patent, protrusions are used to space the ladder from the side of the building. Pins provide a pivotable connection for the folding action of the ladder.
During an emergency, however, valuable time is wasted as the occupant searches for the escape ladder and positions it outside of the building. This time period can be further prolonged if the occupant is injured or otherwise weakened. A long ladder is heavier than a short ladder, further adding to the difficulty in moving the ladder. Additionally, as the ladder is extended from the building to its unfolded state, the side of the building tends to impede the extension of the rungs.
A foldable escape ladder which is easily extendible and quickly operated during an emergency evacuation of a building would be a significant contribution to the art.